1. Don't give it unless there is a real fever. Many babies don't need anything after shots, I think I've only given meds once for a shot between both kids.
2. Call your doctor about dosing. This is an 8 week old, it is based on weight. Our office calculates dosage at every appointment to the ml, so it's perfect for their weight at that time. I wouldn't use a generic dosage on an 8 week old.